"reasonable assumptions" is a correct and usable phrase in written English.
You can use "reasonable assumptions" to refer to a set of presumptions based on careful thinking or assessment. For example, "We made several reasonable assumptions about the project's timeline and budget."
On reasonable assumptions, it could exceed the developed world's within seven years.
Collins declined to reveal the substance of those conversations, but reasonable assumptions could be made.
A few reasonable assumptions later, we came up with this spreadsheet.
Sometimes a refined picture of a disease's history has invalidated clinical practices based on apparently reasonable assumptions.
Based on reasonable assumptions for March, Q1 growth in industrial production should be between 0% and 0.1% quarter-on-quarter.
You can, however, make reasonable assumptions and test them against historical data to determine the outcome with some confidence.
Until these and other issues can be settled scientifically -- a process that may take weeks -- health officials can only give advice and act on reasonable assumptions.
The reasonable assumptions were that Sinn Fein could deliver its military counterpart, the I.R.A., and that steps toward disarmament would be taken well before the May 2000 deadline.
This figure rises to 61% – or 7m households – if the analysis is run on "reasonable assumptions" that the changes Trump has suggested go ahead.
The study takes a more or less typical mortgage securitization sold at the peak of the market, and applies different, but still reasonable, assumptions about the future.
The estimate Unger comes up with, under various reasonable assumptions, that a Higgs boson is produced somewhere in the atmosphere about once every 8 seconds¹.
